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# $Id: camerabase.py,v 1.1 2005/05/12 12:58:28 mbaas Exp $
## \file camerabase.py
## Contains the CameraBase class.
"""This module contains the CameraBase class."""
from Interfaces import *
import protocols
import slots
from cgtypes import *
from math import pi
from worldobject import WorldObject
from scene import getScene
import _core
# CameraBase
class CameraBase(WorldObject):
"""Base class for camera objects.
"""
def __init__(self,
auto_nearfar = True,
nearplane = 0.1,
farplane = 1000,
**params):
WorldObject.__init__(self, **params)
self.nearplane_slot = slots.DoubleSlot(nearplane)
self.farplane_slot = slots.DoubleSlot(farplane)
self.autonearfar_slot = slots.BoolSlot(auto_nearfar)
self.addSlot("nearplane", self.nearplane_slot)
self.addSlot("farplane", self.farplane_slot)
self.addSlot("autonearfar", self.autonearfar_slot)
# "output" property...
exec slots.slotPropertyCode("nearplane")
exec slots.slotPropertyCode("farplane")
exec slots.slotPropertyCode("autonearfar")
def protocols(self):
return [ISceneItem, IComponent, IWorldObject, ICamera]
# eyeRay
def eyeRay(self, x0, y0, width, height):
"""Return a ray from the eye position through an image point.
This method returns a ray whose origin is at the eye position
and that goes through a given point on the image plane. The
point on the plane is given by (x0, y0) which each ranges from
0 to 1. (0,0) is at the upper left and (1,1) at the lower right.
The arguments width and height determine the ratio of the image
plane (the absolute values of width and height are irrelevant).
The return value is a 2-tuple (p,u) where p is the ray origin
and u the normalized direction. Both vectors are given in world
space.
"""
V = self.viewTransformation()
P = self.projection(width, height, 1, 10)
R = mat4().rotation(pi, vec3(0,1,0))
if getScene().handedness=='l':
S = mat4().scaling(vec3(-1,1,1))
I = (P*S*R*V).inverse()
else:
I = (P*R*V).inverse()
x = 2.0*x0-1.0
y = 1.0-2.0*y0
q = I*vec3(x,y,0)
p = self.worldtransform[3]
p = vec3(p.x, p.y, p.z)
return (p, (q-p).normalize())
# getNearFar
def getNearFar(self):
"""Return the distances to the near and far clipping plane.
If auto_nearfar is True, the near/far values are computed from
the scene extent, otherwise the stored values are used.
Compute near and far clipping plane distances from the bounding
box of the scene. The scene bounding box is converted to a
bounding sphere and the near and far clipping planes are set
as tangent planes to the bounding sphere.
"""
if not self.autonearfar:
return self.nearplane, self.farplane
# Get the bounding box of the entire scene
bbox = getScene().boundingBox()
# Determine bounding sphere
bmin,bmax = bbox.getBounds()
if bmin!=None and bmin!=bmax:
# Box center (resp. sphere center)
c = 0.5*(bmin+bmax)
# Radius of the bounding sphere
r = (bmax-c).length()
else:
c = vec3(0,0,0)
r = 10
# Transformation World->Camera
VT = self.viewTransformation()
# minnear = (bmax-bmin).length()/1000
minnear = self.nearplane
minfar = minnear+1
# cz: Depth of the center point
cz = (VT*c).z
near = max(cz-r, minnear)
far = max(cz+r, minfar)
if (far-near)<0.01:
far+=1
return (near,far)
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